mariano spent 20 years in the u.s. navy and served in the persian war before retiring from the service. >> he's a very quiet and nice guy. all i know is just go to work, home, work, home. >> reporter: those who knew mariano say they can't think of a reason why anyone would want to kill him. the shooting comes five days after another shooting in downtown oakland. there does not appear to be any connection between that shooting and this morning's. >> there's no evidence, no witnesses suggesting this case could be suggested. on the first case, there was a robbery that went bad. >> reporter: the city is offering a $10,000 reward for any information that leads to an arrest in this morning's shooting. police are asking anyone with any information to please give them a call. reporting live in oakland, rob roth, ktvu channel 2 news. >>> an investigation is on the way this evening into the cause of a large fire early this morning that seriously damaged a house under construction in the oakland hills. it was reported just after